GHSA-4qpj-gxxg-jqg4
Swiftmailer Sendmail transport arbitrary shell execution
Blast Radius
swiftmailer/swiftmailerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Prior to 5.2.1, the sendmail transport (Swift_Transport_SendmailTransport) was vulnerable to an arbitrary shell execution if the "From" header came from a non-trusted source and no "Return-Path" is configured. This has been fixed in 5.2.1. If you are using sendmail as a transport, you are encouraged to upgrade as soon as possible.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | swiftmailer/swiftmailer | ≥ 4.0.0&&< 5.2.1 | 5.2.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for swiftmailer/swiftmailer. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update swiftmailer/swiftmailer to 5.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4qpj-gxxg-jqg4 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-4qpj-gxxg-jqg4 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-4qpj-gxxg-jqg4. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-4qpj-gxxg-jqg4 in your dependencies?
O3 detects GHSA-4qpj-gxxg-jqg4 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.